A system for propelling an air-driven projectile from an air gun includes an air gun with an elongate bore and a source of compressed air in fluid communication with the elongate bore. A projectile is disposed within the bore of the air gun, the projectile having an outer diameter that is less than an inner diameter of the elongate bore.

An apparatus includes an energy source and an expansion structure. The energy source is configured to convey an amount of energy operable to increase a pressure of a compressible gas disposed in a chamber. The expansion structure is configured to be placed in fluid communication with the chamber and to receive a flow of the compressible gas in response to the increase in pressure. The expansion structure includes an inlet having a first diameter and an outlet having a second diameter greater than the first diameter and is configured to allow the compressible gas to expand as the compressible gas flows from the inlet to the outlet such that a supersonic free jet of the compressible gas exits the outlet. In some instances, the supersonic free jet of the compressible gas can accelerate, relative to the expansion structure, a projectile disposed outside of the expansion structure.

A projectile system has a projectile with a metal body having a first outside diameter, a forward end and a rearward end, a plastic base wad engaged at the rearward end, the plastic base wad of solid plastic having a first length and a second outside diameter, greater than the first outside diameter, and a rifled barrel having a third inside diameter at the tips of the rifling, the third inside diameter greater than the first outside diameter but less than the second outside diameter, and a fourth diameter at the root of the rifling greater than the second outside diameter. With the projectile translating along the rifled barrel, the metal body passes inside the rifling, avoiding metal to metal friction, while the plastic base wad fully engages the rifling, imparting rotation to the metal projectile.

An inventive system comprising a pistol crossbow, a blowgun, a first gas seal operatively associated with said blowgun, and a first pistol crossbow bolt selectively operatively associated with said pistol crossbow and said blowgun, said first pistol crossbow bolt configured to be capable of being selectively operatively interchanged between said pistol crossbow and said blowgun for elastic launching by said pistol crossbow and pneumatic launching by said blowgun. It may further be seen in view of this disclosure that within the scope and the spirit of the inventive disclosure and the claims appended hereunto are inventive system and method examples including, but not limited to, a method of driving a hardware fastener and/or providing a hardware fastener driving system, a system and method for a PPECS stabilizer acceleration interface, and a gas seal comprising a bulkhead and a label configured to be capable of being mounted to said bulkhead.

An apparatus includes an energy source and an expansion structure. The energy source is configured to convey an amount of energy operable to increase a pressure of a compressible gas disposed in a chamber. The expansion structure is configured to be placed in fluid communication with the chamber and to receive a flow of the compressible gas in response to the increase in pressure. The expansion structure includes an inlet having a first diameter and an outlet having a second diameter greater than the first diameter and is configured to allow the compressible gas to expand as the compressible gas flows from the inlet to the outlet such that a supersonic free jet of the compressible gas exits the outlet. In some instances, the supersonic free jet of the compressible gas can accelerate, relative to the expansion structure, a projectile disposed outside of the expansion structure.

The present invention provides a method of making a metal injection molded ammunition cartridge comprising the steps of: providing an ammunition cartridge mold comprising a bottom portion having a primer recess extending into the bottom portion adapted to receive a primer, a flash hole positioned in the primer recess through the bottom surface; side walls extending from the bottom portion to a nose end aperture, wherein a propellant chamber is formed between the nose end aperture and the bottom surface; injecting a metal composition into the ammunition cartridge mold to form a metal injection molded ammunition cartridge; and removing the metal injection molded ammunition cartridge from the ammunition cartridge mold.

An ammunition assembly is provided, which includes a projectile and a fixture, where the projectile includes a penetrating, a sabot and a sabot holder, the sabot is sleeved on an outside of the penetrating, the sabot is of a split structure, the sabot holder is sleeved on an outside of the sabot, the sabot holder is located at one end of the sabot far away from the penetrating; the projectile is slidably provided in the chamber; the fixture includes clamping blocks, the clamping blocks are movably provided in the gun barrel, and the clamping blocks are capable of extending into the chamber and blocking the sabot holder.

A rear slip base plate for a round carrying a guidance and control unit payload, which round is launched from a rifled launch tube. To prevent the guidance and control unit payload from also being rapidly spun with the round, the slip base plate unit mechanically isolates the guidance and control unit payload from the round spin rate.

A projectile for loading into a rifled barrel includes a casing having a cylindrical body, a forward aerodynamic end, and a free end opposite the aerodynamic end, the cylindrical body of the casing defining an interior cavity extending to and in open communication with the free end. The projectile also has a bullet sized to initially slidably engage the casing along a partial length of the interior cavity through the free end. Upon discharge of propellant, the bullet is forced to slidably engage the casing farther within the cavity, preferably such that an entire length of the bullet is housed within the casing cavity, whereby a circumference of the casing is increased such that the increased circumference of the casing catches barrel rifling of the muzzleloader rifle. This allows a smaller caliber bullet to be used in a fouled barrel, while increasing accuracy of the muzzleloader rifle.

The present invention provides a method of making a metal injection molded ammunition cartridge comprising the steps of: providing an ammunition cartridge mold comprising a bottom portion having a primer recess extending into the bottom portion adapted to receive a primer, a flash hole positioned in the primer recess through the bottom surface; side walls extending from the bottom portion to a nose end aperture, wherein a propellant chamber is formed between the nose end aperture and the bottom surface; injecting a metal composition into the ammunition cartridge mold to form a metal injection molded ammunition cartridge; and removing the metal injection molded ammunition cartridge from the ammunition cartridge mold.